Commit a786ab36 authored by Matias Ezequiel Vara Larsen's avatar Matias Ezequiel Vara Larsen Committed by David S. Miller
Browse files

vsock/virtio: add support for MSG_PEEK 



This patch adds support for MSG_PEEK. In such a case, packets are not
removed from the rx_queue and credit updates are not sent.

Signed-off-by: default avatarMatias Ezequiel Vara Larsen <matiasevara@gmail.com>
Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Tested-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 67879919

net/vmw_vsock/virtio_transport_common.c

+52 −3
Original line number Diff line number Diff line
@@ -263,6 +263,55 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk, 
	return virtio_transport_send_pkt_info(vsk, &info);

}



static ssize_t

virtio_transport_stream_do_peek(struct vsock_sock *vsk,

				struct msghdr *msg,

				size_t len)

{

	struct virtio_vsock_sock *vvs = vsk->trans;

	struct virtio_vsock_pkt *pkt;

	size_t bytes, total = 0, off;

	int err = -EFAULT;



	spin_lock_bh(&vvs->rx_lock);



	list_for_each_entry(pkt, &vvs->rx_queue, list) {

		off = pkt->off;



		if (total == len)

			break;



		while (total < len && off < pkt->len) {

			bytes = len - total;

			if (bytes > pkt->len - off)

				bytes = pkt->len - off;



			/* sk_lock is held by caller so no one else can dequeue.

			 * Unlock rx_lock since memcpy_to_msg() may sleep.

			 */

			spin_unlock_bh(&vvs->rx_lock);



			err = memcpy_to_msg(msg, pkt->buf + off, bytes);

			if (err)

				goto out;



			spin_lock_bh(&vvs->rx_lock);



			total += bytes;

			off += bytes;

		}

	}



	spin_unlock_bh(&vvs->rx_lock);



	return total;



out:

	if (total)

		err = total;

	return err;

}



static ssize_t

virtio_transport_stream_do_dequeue(struct vsock_sock *vsk,

				   struct msghdr *msg,
@@ -335,8 +384,8 @@ virtio_transport_stream_dequeue(struct vsock_sock *vsk, 
				size_t len, int flags)

{

	if (flags & MSG_PEEK)

		return -EOPNOTSUPP;



		return virtio_transport_stream_do_peek(vsk, msg, len);

	else

		return virtio_transport_stream_do_dequeue(vsk, msg, len);

}

EXPORT_SYMBOL_GPL(virtio_transport_stream_dequeue);